1. Field of the Invention
Aspects of the present invention relates to a method of fabricating GaN, and more particularly, to a method of forming porous GaN and a method of fabricating thick GaN using the same.
2. Description of the Related Art
A variety of methods of fabricating GaN for use as substrates for blue or UV-based light emitting devices have been proposed. In most conventional methods of fabricating GaN, porous GaN is formed on a substrate, such as an SiC substrate or a sapphire substrate. Then, thick GaN is grown on the porous GaN.
Mynbaeva et al. suggest a method of growing GaN on an SiC substrate. The method uses a HF solution under ultraviolet light excitation to form porous GaN. This method requires a separate wet etching process in addition to a film formation process, thus necessitating an additional cleaning process (Strain relaxation in GaN Layers grown on porous GaN sublayers (MRS Internet J. Nitride Semicond. Res. 4, 14(1999)))
Xiuling Li et al. suggest a method of forming porous GaN using metal-assisted electroless wet etching using a metal such as Pt, etc. This method also requires additional processes of forming a metallic layer and etching. Thus, the processes are complicated. (In-plane bandgap control in porous GaN through electroless wet chemical etching (Volume 80, Number 6, 11 Feb. 2002, Applied Physics Letters))
Yuichi Oshima et al. suggest a method of porous GaN using an ex-situ process using metal such as Ti, etc. This method also involves complicated and expensive processes. (Preparation of Freestanding GaN Wafers by Hydride Vapor Phase Epitaxy with Void-Assisted Separation(Jpn. J. Appl. Phys. Vol. 42 (2003) pp. L1-L3 Part 2, No. 1A/B, 15 Jan. 2003))